Oil squirters are used in engines to provide a directed flow of lubrication to a portion of the engine. In a typical configuration, an oil squirter may be provided in each engine cylinder, and may be configured to squirt oil through a nozzle to lubricate cylinder bore walls, especially during cold start, to prevent or reduce engine piston slap and noise therefrom. The oil squirter may direct a flow of lubrication to the engine piston, especially when the engine is operating at high speeds and/or hot temperatures, to cool the engine piston.
An oil squirter may include a nozzle in fluid communication with a valve body including a check valve, which may also be referred to as a one-way valve. The check valve includes a stopper, which may be configured as a ball or piston spring loaded or biased against a sealing interface or seat, to seal an orifice in communication with a pressurized oil source. When the oil pressure rises sufficiently to offset the spring bias, the stopper is displaced from the sealing interface such that oil flows through the orifice and valve body to exit out of the nozzle thereby providing lubrication to the engine cylinder and/or engine piston. The oil pressure at which the stopper is displaced from the sealing interface to allow oil flow past the sealing interface is referred to as the cracking pressure. At lower oil pressures, e.g., below the cracking pressure, the oil pressure is insufficient to overcome the spring bias and the orifice remains sealed by the stopper preventing oil flow through the squirter. The oil squirter may be configured with a cracking pressure which is above the oil pressure during normal driving conditions, e.g., driving conditions other than cold start, high heat, high speed, and the like, to prevent diversion of oil from other areas of the engine requiring lubrication and/or additional aeration of oil in the engine cylinder during normal driving conditions. Variability in the opening and closing of the stopper may cause fluctuations in oil flow rate through the valve above the cracking pressure.
Variability in the opening and closing of the stopper in the oil squirter may generate noise. For example, oscillation of the stopper during opening or closing may result in repetitive or cyclic contact between the stopper and the sealing interface, which may generate noise until the stopper is displaced sufficiently from the sealing interface to avoid contact of the stopper with the interface during oscillation, and to stabilize the flow of oil through the squirter valve. The cyclic contact may cause wear of one or both of the stopper and the sealing interface, which may create a leakage path through the sealing interface and/or reduce the cracking pressure of the squirter valve. A reduction in the cracking pressure may cause diversion of oil pressure through the squirter valve such that other areas of the engine may become under lubricated. Variability in the flow of oil through the squirter valve due to oscillation of the stopper may cause oscillations or fluctuations in the engine system oil pressure. Oscillation and/or excessive wear may cause binding or jamming of the stopper within the valve body, which may result in excessive oil flow through the squirter into the engine cylinder, blockage of the squirter valve resulting in oil starvation to the engine cylinder, and/or stopper breakage. Oil squirter noise, binding or breakage may result in customer complaints and/or customer dissatisfaction.
Variability in the opening and closing of the stopper may be reduced, for example, by constraining or damping the oscillating movement of the stopper using a damping surface in contact with the stopper, such as a secondary seat or interface proximate to the stopper. This approach may be disadvantaged by introducing another surface in contact with the stopper, adding additional cost as well as increasing the potential for wear and/or binding of the stopper due to contact with the secondary surface.